The fluoridation system that was shut down last year at a Gilbert water-treatment plant likely failed because of faulty engineering that posed a possible health hazard to employees, according to town documents and statements from two former water division employees.

When Gilbert voters approved fluoridation in 2000, the town’s only treatment plant wasn’t properly suited to inject fluoride, a cavity-fighting chemical, into the water supply, according to a memo that then-Public Works Director Lonnie Frost wrote to Assistant Town Manager Marc Skocypec last month.

Citing health concerns, then-Water Manager Chris Ochs shut down the fluoridation system at Gilbert’s North Water Treatment Plant on July 16, 2011.

Although Ochs told The Arizona Republic in an interview that he informed Frost of the problem, the news apparently didn’t reach upper management until August of this year, 13 months after the shutdown.

Both Ochs and Frost were put on paid leave last month while the town investigated the stoppage. Ochs was later fired, and Frost retired after 28 years with the town. Frost declined repeated requests from The Republic for comment.

Town officials opted to convert a system designed for adjusting pH levels, but the equipment wasn’t contained within a separate, well-ventilated room as fluoridation systems typically are, Frost’s memo said.

As pipes, fittings and gauges on the pumping system began to corrode, white powder formed on the equipment, causing a burning sensation in workers’ eyes, nose and skin, the memo said.

Tests conducted in August 2011 — one month after officials halted fluoridation — found evidence in the powder of the hazardous chemical hydrofluorosilicic acid, which had apparently evaporated and crystallized, according to an industrial hygiene report by IHI Environmental.

Prolonged exposure to the acid can cause bone changes, ulcers, damage to mucous membranes, shock, coma and death, according to a safety sheet from chemical distributor ClearTech Industries.

Multiple inspections from outside experts detected health concerns and engineering problems at the plant, which began fluoridation in February 2002.

Although a Gilbert Fire Department hazardous materials team found “no immediate risk” to life around the fluoride system, it was concerned enough to recommend that any employees entering the area wear protective clothing and respirators.

A private engineering firm reported multiple concerns with the system, including multiple leaks and an undersize ventilation fan in the makeshift enclosure built around the pump, according to town documents.

The industrial hygienist, meanwhile, said workers with duties in the pump room should “thoroughly wash their hands and face” before eating, drinking or using the restroom, according to the report.

Although airborne contaminant levels in the fluoridation area were below regulatory levels, the hygienist noted that the fluoride pump was inactive during the testing. “Conditions … while the (hydrofluorosilicic) acid pumping process is operational are unknown and should be assumed to be hazardous,” the report says.

Ochs said he shut down the system to avoid putting employees at risk and pushed for funding to get it fixed. But Ochs also said he was stonewalled by Frost, his boss.

Within a few months of the fluoridation shutdown, Ochs received a cost estimate of about $100,000 to replace the system and asked to move forward with the fix, he said. Frost told him to wait, however, until the next fiscal year, which began July 1, Ochs said.

“I was trying to do what he said,” Ochs said. “Now they’re coming to the conclusion I should have gone over his head, and that’s fine, but I didn’t.”

Former Gilbert Water Superintendent William Taylor, who helped launch the town’s fluoride operation in 2002, seemed to confirm Ochs’ claim that the fluoride system was inadequate in an e-mail to Town Council members on Sept 8.

“The fluoridation system that exists today at the North WTP cannot work in its present configuration — a poor engineering plan,” wrote Taylor, who retired from Gilbert a few years ago. “This is something that should have been taken care of, and there is no defense for that.”

Taylor declined to comment when contacted by The Republic.

Taylor’s e-mail to the council pointed to the Santan Vista Water Treatment Plant, which Gilbert and Chandler operate jointly and opened in 2009, as evidence that fluoridation can be managed successfully despite inherent issues with hydrofluorosilicic acid.

The chemical itself might be “the most extremely hazardous chemical on the treatment plant site,” Taylor said.

Gilbert spokeswoman Dana Berchman said the town has started work to get the fluoride system back up. An engineering company is expected to finish designs for the new system by the end of the month, and construction is expected to take 30 to 60 days, she said.

The town’s “reasonable expectation” should have been to build the fluoride system right the first time, 10 years ago,Ochs said.

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